1. Field of the Invention
This invention relates to a process for manufacturing glass with functional coating, and also to a process for manufacturing a combiner for head-up display (HUD) using such glass.
2. Discussion of Background
As a method for providing a base plate (or substrate) such as glass, etc. with a metal oxide thin film coating, there have so far been known various methods such as vapor-deposition method, sputtering method, and other physical expedients; or the wet coating methods such as the immersing method, roll-coating method, meniscus-coating method, and so forth, wherein a liquid containing therein a material which can be turned into a metal oxide is applied onto the substrate; or various other methods. While the wet coating methods are advantageous in that they contribute to a reduced cost of manufacturing in comparison with the physical expedients, both wet-coating methods and the physical coating methods are disadvantageous in that, when it is desired to form a film on one part alone of the base plate having a wide area, with good outer appearance, the remaining part of the substrate where no film is to be formed should be masked during the film formation, or the film as formed over the entire substrate should be removed by etching after the film formation, leaving only the portion where the film formation is intended. This would, after all, lead to complicated manufacturing process, hence increased production cost. Further, since the viscosity of the liquid used for the wet-coating methods is high, good levelling properties (which produce a flat even surface) could not be obtained.